JPS58158849A - Ion gun power source - Google Patents

Abstract

PURPOSE:To reduce the size of a power source by constructing an acceleration power source and an electrostatic lens power source integrally. CONSTITUTION:The divided voltage output (e) taken out from an intermediate tap provided at the secondary of a booster is boosted by Cockcroft circuit where Cockcroft circuits comprised of capacitors C1, C2 and diodes D1, D2 are connected in N stages (N is integer). While the secondary output E from the booster T is boosted by second Cockcroft circuit where Cockcroft circuits comprised of capacitors Cs1, Cs2 and diodes Ds1, Ds2 are connected in M stages (M is integer). The final stage output from the second Cockcroft circuit is applied on an emitter as the accelerating voltage. Since the output resistance of Cockcroft circuit is low, stable acceleration voltage can be obtained. Random division voltage is applied as the electrostatic lens voltage onto the electrostatic lens from the division terminal of the first Cockcroft circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power source for an ion gun that can be used as an acceleration power source for an ion beam acceleration system and as a power source for an electrostatic lens.

In an ion gun, an Einzel lens to which a high voltage of the same polarity as the voltage for accelerating the ion beam is applied is usually used as an electrostatic lens that forms an ion probe. An electrostatic lens power source for driving such an electrostatic lens is generally provided separately from an acceleration power source for accelerating the ion beam. FIG. 1 is a diagram showing the power supply system of such an ion gun. In the figure, 1 is the crucible 2
An ion beam generating emitter 3 provided at the tip of the crucible 2 is a heating power source for heating the crucible 2 . 4 is an extraction electrode, 5 is an extraction power source that applies an extraction voltage to the extraction electrode, and 6 is an acceleration power source that provides an acceleration voltage for accelerating the ion beam to the emitter 1. 7 is a ground electrode, 8 is an electrostatic lens, 9 is a power source for the electrostatic lens, and 10 is a sample. One pole of the heating power supply 3 and the positive pole sides of the extraction power supply 5 and the acceleration power supply 6 are respectively commonly connected. In the conventional power supply system as shown in the figure, the electrostatic lens power supply 9 is replaced by the acceleration power supply 6.
The device is expensive because it needs to be installed separately.

For this reason, a tapped bleeder resistor is provided in the acceleration power source to divide and extract the output voltage of the acceleration power source, and the divided voltage is used as a voltage for the electrostatic lens. FIG. 2 is an explanatory diagram showing the configuration of this type of power supply system. In the figure, the same parts as in FIG. 1 are given the same reference numerals.

In the figure, 11 is the bleeder resistor for partial pressure described above. In such a system, since the resistor 11 consumes power, it is necessary to increase the capacity of the acceleration power source 6. Further, unless a considerable current is passed through the bleeder resistor 11, a stable voltage cannot be applied to the electrostatic lens 8. Therefore, the capacity of the accelerating power source 6 becomes enormous, making the device larger.

The present invention has been made in view of the above points, and the present invention has been made in view of the above points.
A Kotsukucroft circuit and a second Kotsukucroft circuit having the first Kotsukucroft circuit as a part of the configuration are constructed, and the voltage obtained by dividing the output of the first Kotsukucroft circuit is used as a power supply for an electrostatic lens, and a second Kotsukucroft circuit is used. A power source for an ion gun with a simple configuration that can supply a stable electrostatic lens current by using the circuit output as an accelerating power source has been realized.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 3 is an electrical configuration diagram showing one embodiment of the present invention. In the figure, the main character is a step-up transformer with an intermediate tap on its secondary side. The divided voltage output e taken out from the center tap is connected to capacitors CI, C2 and diode D+.
, D2 are connected in N stages (N is an integer) to boost the voltage. As shown in the figure, the first Kotscroft circuit is provided with voltage dividing terminals for each stage. On the other hand, the secondary output E of the step-up transformer T is boosted by a second Kotscroft circuit in which M stages (M is an integer) are connected to each other. be done. Here, a part of the first Kotscroft circuit is used as is as the capacitor C82. For example, in the figure, the combined capacitance of the first four Kotscroft stages is the capacitor C82. The final stage output of the second Kotscroft circuit configured in this manner is applied to the emitter as an accelerating voltage. Since the output resistance of the Kotscroft circuit is low, a stable acceleration voltage can be obtained. On the other hand, the first
An arbitrary divided voltage is applied to the electrostatic lens as an electrostatic lens voltage from the voltage dividing terminal of the Kotscroft circuit. R
s is a variable resistor for fine adjustment, and R2 is a protective resistor. In the figure, both ends of the variable resistor R1 slide on the voltage dividing terminals of the first Kotscroft circuit to obtain an arbitrary divided voltage.

Even in this case, since the output resistance of the extracted divided voltage is small, a stable voltage for the electrostatic lens can be obtained.

FIG. 4 is an electrical configuration diagram showing an example of a specific configuration of an ion gun power supply system using the present invention.

In the figure, 20 is the power supply circuit shown in FIG. R
s and R4 are high voltage detection resistors, and 21 is a comparison unit that compares the detected voltage with the reference voltage 1S. 22 is a DC power supply, 2
Reference numeral 3 denotes a control section which receives the output of the DC power supply and the comparison section 21 and outputs a stable DC voltage. 24 is an oscillator that receives the output of the control unit and outputs high-frequency alternating current according to the output;
Its output is applied to the step-up transformer T of the power supply circuit 20.

By forming such a feedback loop, highly stable acceleration voltages and electrostatic lens voltages can be obtained. As described above, in the present invention, since the acceleration power source and the electrostatic lens power source are integrated, the power source itself can be miniaturized.

In the above description, the first Kotscroft circuit 4 is used as the capacitor Cs2 of the second Kotscroft circuit.
Although the number of stages is used, there is no need to be limited to this, and any other number of stages may be used. Further, it goes without saying that the present invention can be used as it is not only as a power source for a positive ion gun but also as a power source for a negative ion gun.

As explained above, the power supply for an ion gun of the present invention is composed of a first Kotskucroft circuit and a second Kotskucroft circuit that includes the first Kotskucroft circuit as a part of its configuration. The divided voltage of the output is used as a power source for an electrostatic lens, and the output of the second Kotscroft circuit is used as an acceleration power source.According to the present invention, it is possible to realize a power source for an ion gun with a simple configuration. can.

[Brief explanation of the drawing]

Figures 1 and 2 are explanatory diagrams showing the connection of conventional power supplies;
The figure is an electrical connection diagram showing one embodiment of the present invention, and FIG. 4 is a specific configuration diagram. 1... Emitter 2... Crucible 3... Heating power source 4... Extracting electrode 5... Extracting power source
6... Acceleration power supply 7... Ground electrode 8...
・Electrostatic lens 9... Electrostatic lens power supply 10... Sample 11... Leader resistor 20
... Power supply circuit 21 ... Comparison section 22 ... DC power supply 23 ... Control section 24 ... High frequency oscillator
T...Step-up transformer Cs-G21 CS2I
CS 2 = Capacitor R1... Voltage dividing resistance
R2-R4...Resistance patent applicant JEOL Co., Ltd. Representative Patent attorney Toji Ijima M1 diagram M3 diagram Takashu Hori text: L

Claims (1)

[Claims] A first Kottscroft circuit with an N-stage configuration that boosts a part of the secondary output of a step-up transformer, with a voltage dividing terminal for each stage, and an M-stage configuration that boosts all of the secondary output. and a second Kotskucroft circuit that includes the first Kotskucroft circuit as a part of its configuration, the divided voltage output of the first Kotsukucroft circuit is used as a power supply for the electrostatic lens, and the second Kotsukucroft circuit A power source for an ion gun, characterized in that a Kotsukucroft circuit output is used as an acceleration power source.